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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package javax.swing;

import java.awt.Font;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.awt.Color;
import java.awt.Component;
import java.awt.SystemColor;
import java.awt.Toolkit;
import sun.awt.SunToolkit;

import javax.swing.text.*;
import javax.swing.border.*;
import javax.swing.plaf.*;

import java.net.URL;
import sun.swing.SwingUtilities2;
import sun.swing.DefaultLayoutStyle;
import sun.swing.ImageIconUIResource;

import java.util.StringTokenizer;


/**
 * {@code LookAndFeel}, as the name implies, encapsulates a look and
 * feel. Beyond installing a look and feel most developers never need to
 * interact directly with {@code LookAndFeel}. In general only developers
 * creating a custom look and feel need to concern themselves with this class.
 * <p>
 * Swing is built upon the foundation that each {@code JComponent}
 * subclass has an implementation of a specific {@code ComponentUI}
 * subclass. The {@code ComponentUI} is often referred to as "the ui",
 * "component ui", or "look and feel delegate". The {@code ComponentUI}
 * subclass is responsible for providing the look and feel specific
 * functionality of the component. For example, {@code JTree} requires
 * an implementation of the {@code ComponentUI} subclass {@code
 * TreeUI}. The implementation of the specific {@code
 * ComponentUI} subclass is provided by the {@code LookAndFeel}. Each
 * {@code JComponent} subclass identifies the {@code ComponentUI}
 * subclass it requires by way of the {@code JComponent} method {@code
 * getUIClassID}.
 * <p>
 * Each {@code LookAndFeel} implementation must provide
 * an implementation of the appropriate {@code ComponentUI} subclass by
 * specifying a value for each of Swing's ui class ids in the {@code
 * UIDefaults} object returned from {@code getDefaults}. For example,
 * {@code BasicLookAndFeel} uses {@code BasicTreeUI} as the concrete
 * implementation for {@code TreeUI}. This is accomplished by {@code
 * BasicLookAndFeel} providing the key-value pair {@code
 * "TreeUI"-"javax.swing.plaf.basic.BasicTreeUI"}, in the
 * {@code UIDefaults} returned from {@code getDefaults}. Refer to
 * {@link UIDefaults#getUI(JComponent)} for details on how the implementation
 * of the {@code ComponentUI} subclass is obtained.
 * <p>
 * When a {@code LookAndFeel} is installed the {@code UIManager} does
 * not check that an entry exists for all ui class ids. As such,
 * random exceptions will occur if the current look and feel has not
 * provided a value for a particular ui class id and an instance of
 * the {@code JComponent} subclass is created.
 *
 * <h2>Recommendations for Look and Feels</h2>
 *
 * As noted in {@code UIManager} each {@code LookAndFeel} has the opportunity
 * to provide a set of defaults that are layered in with developer and
 * system defaults. Some of Swing's components require the look and feel
 * to provide a specific set of defaults. These are documented in the
 * classes that require the specific default.
 *
 * <h3><a name="defaultRecommendation">ComponentUIs and defaults</a></h3>
 *
 * All {@code ComponentUIs} typically need to set various properties
 * on the {@code JComponent} the {@code ComponentUI} is providing the
 * look and feel for. This is typically done when the {@code
 * ComponentUI} is installed on the {@code JComponent}. Setting a
 * property should only be done if the developer has not set the
 * property. For non-primitive values it is recommended that the
 * {@code ComponentUI} only change the property on the {@code
 * JComponent} if the current value is {@code null} or implements
 * {@code UIResource}. If the current value is {@code null} or
 * implements {@code UIResource} it indicates the property has not
 * been set by the developer, and the ui is free to change it.  For
 * example, {@code BasicButtonUI.installDefaults} only changes the
 * font on the {@code JButton} if the return value from {@code
 * button.getFont()} is {@code null} or implements {@code
 * UIResource}. On the other hand if {@code button.getFont()} returned
 * a {@code non-null} value that did not implement {@code UIResource}
 * then {@code BasicButtonUI.installDefaults} would not change the
 * {@code JButton}'s font.
 * <p>
 * For primitive values, such as {@code opaque}, the method {@code
 * installProperty} should be invoked.  {@code installProperty} only changes
 * the corresponding property if the value has not been changed by the
 * developer.
 * <p>
 * {@code ComponentUI} implementations should use the various install methods
 * provided by this class as they handle the necessary checking and install
 * the property using the recommended guidelines.
 *
 * <h3><a name="exceptions"></a>Exceptions</h3>
 *
 * All of the install methods provided by {@code LookAndFeel} need to
 * access the defaults if the value of the property being changed is
 * {@code null} or a {@code UIResource}. For example, installing the
 * font does the following:
 * <pre>
 *   JComponent c;
 *   Font font = c.getFont();
 *   if (font == null || (font instanceof UIResource)) {
 *       c.setFont(UIManager.getFont("fontKey"));
 *   }
 * </pre>
 * If the font is {@code null} or a {@code UIResource}, the
 * defaults table is queried with the key {@code fontKey}. All of
 * {@code UIDefault's} get methods throw a {@code
 * NullPointerException} if passed in {@code null}. As such, unless
 * otherwise noted each of the various install methods of {@code
 * LookAndFeel} throw a {@code NullPointerException} if the current
 * value is {@code null} or a {@code UIResource} and the supplied
 * defaults key is {@code null}. In addition, unless otherwise specified
 * all of the {@code install} methods throw a {@code NullPointerException} if
 * a {@code null} component is passed in.
 *
 * @author Tom Ball
 * @author Hans Muller
 */
public abstract class LookAndFeel {

  /**
   * Convenience method for setting a component's foreground
   * and background color properties with values from the
   * defaults.  The properties are only set if the current
   * value is either {@code null} or a {@code UIResource}.
   *
   * @param c component to set the colors on
   * @param defaultBgName key for the background
   * @param defaultFgName key for the foreground
   * @throws NullPointerException as described in <a href="#exceptions">exceptions</a>
   * @see #installColorsAndFont
   * @see UIManager#getColor
   */
  public static void installColors(JComponent c,
      String defaultBgName,
      String defaultFgName) {
    Color bg = c.getBackground();
    if (bg == null || bg instanceof UIResource) {
      c.setBackground(UIManager.getColor(defaultBgName));
    }

    Color fg = c.getForeground();
    if (fg == null || fg instanceof UIResource) {
      c.setForeground(UIManager.getColor(defaultFgName));
    }
  }


  /**
   * Convenience method for setting a component's foreground,
   * background and font properties with values from the
   * defaults.  The properties are only set if the current
   * value is either {@code null} or a {@code UIResource}.
   *
   * @param c component set to the colors and font on
   * @param defaultBgName key for the background
   * @param defaultFgName key for the foreground
   * @param defaultFontName key for the font
   * @throws NullPointerException as described in <a href="#exceptions">exceptions</a>
   * @see #installColors
   * @see UIManager#getColor
   * @see UIManager#getFont
   */
  public static void installColorsAndFont(JComponent c,
      String defaultBgName,
      String defaultFgName,
      String defaultFontName) {
    Font f = c.getFont();
    if (f == null || f instanceof UIResource) {
      c.setFont(UIManager.getFont(defaultFontName));
    }

    installColors(c, defaultBgName, defaultFgName);
  }


  /**
   * Convenience method for setting a component's border property with
   * a value from the defaults. The border is only set if the border is
   * {@code null} or an instance of {@code UIResource}.
   *
   * @param c component to set the border on
   * @param defaultBorderName key specifying the border
   * @throws NullPointerException as described in <a href="#exceptions">exceptions</a>
   */
  public static void installBorder(JComponent c, String defaultBorderName) {
    Border b = c.getBorder();
    if (b == null || b instanceof UIResource) {
      c.setBorder(UIManager.getBorder(defaultBorderName));
    }
  }


  /**
   * Convenience method for uninstalling a border. If the border of
   * the component is a {@code UIResource}, it is set to {@code
   * null}.
   *
   * @param c component to uninstall the border on
   * @throws NullPointerException if {@code c} is {@code null}
   */
  public static void uninstallBorder(JComponent c) {
    if (c.getBorder() instanceof UIResource) {
      c.setBorder(null);
    }
  }

  /**
   * Convenience method for installing a property with the specified name
   * and value on a component if that property has not already been set
   * by the developer.  This method is intended to be used by
   * ui delegate instances that need to specify a default value for a
   * property of primitive type (boolean, int, ..), but do not wish
   * to override a value set by the client.  Since primitive property
   * values cannot be wrapped with the {@code UIResource} marker, this method
   * uses private state to determine whether the property has been set
   * by the client.
   *
   * @param c target component to set the property on
   * @param propertyName name of the property to set
   * @param propertyValue value of the property
   * @throws IllegalArgumentException if the specified property is not one which can be set using
   * this method
   * @throws ClassCastException if the property value has not been set by the developer and the type
   * does not match the property's type
   * @throws NullPointerException if {@code c} is {@code null}, or the named property has not been
   * set by the developer and {@code propertyValue} is {@code null}
   * @since 1.5
   */
  public static void installProperty(JComponent c,
      String propertyName, Object propertyValue) {
    // this is a special case because the JPasswordField's ancestor hierarchy
    // includes a class outside of javax.swing, thus we cannot call setUIProperty
    // directly.
    if (SunToolkit.isInstanceOf(c, "javax.swing.JPasswordField")) {
      if (!((JPasswordField) c).customSetUIProperty(propertyName, propertyValue)) {
        c.setUIProperty(propertyName, propertyValue);
      }
    } else {
      c.setUIProperty(propertyName, propertyValue);
    }
  }

  /**
   * Convenience method for building an array of {@code
   * KeyBindings}. While this method is not deprecated, developers
   * should instead use {@code ActionMap} and {@code InputMap} for
   * supplying key bindings.
   * <p>
   * This method returns an array of {@code KeyBindings}, one for each
   * alternating {@code key-action} pair in {@code keyBindingList}.
   * A {@code key} can either be a {@code String} in the format
   * specified by the <code>KeyStroke.getKeyStroke</code> method, or
   * a {@code KeyStroke}. The {@code action} part of the pair is a
   * {@code String} that corresponds to the name of the {@code
   * Action}.
   * <p>
   * The following example illustrates creating a {@code KeyBinding} array
   * from six alternating {@code key-action} pairs:
   * <pre>
   *  JTextComponent.KeyBinding[] multilineBindings = makeKeyBindings( new Object[] {
   *          "UP", DefaultEditorKit.upAction,
   *        "DOWN", DefaultEditorKit.downAction,
   *     "PAGE_UP", DefaultEditorKit.pageUpAction,
   *   "PAGE_DOWN", DefaultEditorKit.pageDownAction,
   *       "ENTER", DefaultEditorKit.insertBreakAction,
   *         "TAB", DefaultEditorKit.insertTabAction
   *  });
   * </pre>
   * If {@code keyBindingList's} length is odd, the last element is
   * ignored.
   * <p>
   * Supplying a {@code null} value for either the {@code key} or
   * {@code action} part of the {@code key-action} pair results in
   * creating a {@code KeyBinding} with the corresponding value
   * {@code null}. As other parts of Swing's expect {@code non-null} values
   * in a {@code KeyBinding}, you should avoid supplying {@code null} as
   * either the {@code key} or {@code action} part of the {@code key-action}
   * pair.
   *
   * @param keyBindingList an array of {@code key-action} pairs
   * @return an array of {@code KeyBindings}
   * @throws NullPointerException if {@code keyBindingList} is {@code null}
   * @throws ClassCastException if the {@code key} part of the pair is not a {@code KeyStroke} or
   * {@code String}, or the {@code action} part of the pair is not a {@code String}
   * @see ActionMap
   * @see InputMap
   * @see KeyStroke#getKeyStroke
   */
  public static JTextComponent.KeyBinding[] makeKeyBindings(Object[] keyBindingList) {
    JTextComponent.KeyBinding[] rv = new JTextComponent.KeyBinding[keyBindingList.length / 2];

    for (int i = 0; i < rv.length; i++) {
      Object o = keyBindingList[2 * i];
      KeyStroke keystroke = (o instanceof KeyStroke)
          ? (KeyStroke) o
          : KeyStroke.getKeyStroke((String) o);
      String action = (String) keyBindingList[2 * i + 1];
      rv[i] = new JTextComponent.KeyBinding(keystroke, action);
    }

    return rv;
  }

  /**
   * Creates a {@code InputMapUIResource} from <code>keys</code>. This is
   * a convenience method for creating a new {@code InputMapUIResource},
   * invoking {@code loadKeyBindings(map, keys)}, and returning the
   * {@code InputMapUIResource}.
   *
   * @param keys alternating pairs of {@code keystroke-action key} pairs as described in {@link
   * #loadKeyBindings}
   * @return newly created and populated {@code InputMapUIResource}
   * @see #loadKeyBindings
   * @since 1.3
   */
  public static InputMap makeInputMap(Object[] keys) {
    InputMap retMap = new InputMapUIResource();
    loadKeyBindings(retMap, keys);
    return retMap;
  }

  /**
   * Creates a {@code ComponentInputMapUIResource} from
   * <code>keys</code>. This is a convenience method for creating a
   * new {@code ComponentInputMapUIResource}, invoking {@code
   * loadKeyBindings(map, keys)}, and returning the {@code
   * ComponentInputMapUIResource}.
   *
   * @param c component to create the {@code ComponentInputMapUIResource} with
   * @param keys alternating pairs of {@code keystroke-action key} pairs as described in {@link
   * #loadKeyBindings}
   * @return newly created and populated {@code InputMapUIResource}
   * @throws IllegalArgumentException if {@code c} is {@code null}
   * @see #loadKeyBindings
   * @see ComponentInputMapUIResource
   * @since 1.3
   */
  public static ComponentInputMap makeComponentInputMap(JComponent c,
      Object[] keys) {
    ComponentInputMap retMap = new ComponentInputMapUIResource(c);
    loadKeyBindings(retMap, keys);
    return retMap;
  }


  /**
   * Populates an {@code InputMap} with the specified bindings.
   * The bindings are supplied as a list of alternating
   * {@code keystroke-action key} pairs. The {@code keystroke} is either
   * an instance of {@code KeyStroke}, or a {@code String}
   * that identifies the {@code KeyStroke} for the binding. Refer
   * to {@code KeyStroke.getKeyStroke(String)} for the specific
   * format. The {@code action key} part of the pair is the key
   * registered in the {@code InputMap} for the {@code KeyStroke}.
   * <p>
   * The following illustrates loading an {@code InputMap} with two
   * {@code key-action} pairs:
   * <pre>
   *   LookAndFeel.loadKeyBindings(inputMap, new Object[] {
   *     "control X", "cut",
   *     "control V", "paste"
   *   });
   * </pre>
   * <p>
   * Supplying a {@code null} list of bindings ({@code keys}) does not
   * change {@code retMap} in any way.
   * <p>
   * Specifying a {@code null} {@code action key} results in
   * removing the {@code keystroke's} entry from the {@code InputMap}.
   * A {@code null} {@code keystroke} is ignored.
   *
   * @param retMap {@code InputMap} to add the {@code key-action} pairs to
   * @param keys bindings to add to {@code retMap}
   * @throws NullPointerException if {@code keys} is {@code non-null}, not empty, and {@code retMap}
   * is {@code null}
   * @see KeyStroke#getKeyStroke(String)
   * @see InputMap
   * @since 1.3
   */
  public static void loadKeyBindings(InputMap retMap, Object[] keys) {
    if (keys != null) {
      for (int counter = 0, maxCounter = keys.length;
          counter < maxCounter; counter++) {
        Object keyStrokeO = keys[counter++];
        KeyStroke ks = (keyStrokeO instanceof KeyStroke) ?
            (KeyStroke) keyStrokeO :
            KeyStroke.getKeyStroke((String) keyStrokeO);
        retMap.put(ks, keys[counter]);
      }
    }
  }

  /**
   * Creates and returns a {@code UIDefault.LazyValue} that loads an
   * image. The returned value is an implementation of {@code
   * UIDefaults.LazyValue}. When {@code createValue} is invoked on
   * the returned object, the image is loaded. If the image is {@code
   * non-null}, it is then wrapped in an {@code Icon} that implements {@code
   * UIResource}. The image is loaded using {@code
   * Class.getResourceAsStream(gifFile)}.
   * <p>
   * This method does not check the arguments in any way. It is
   * strongly recommended that {@code non-null} values are supplied else
   * exceptions may occur when {@code createValue} is invoked on the
   * returned object.
   *
   * @param baseClass {@code Class} used to load the resource
   * @param gifFile path to the image to load
   * @return a {@code UIDefaults.LazyValue}; when resolved the {@code LazyValue} loads the specified
   * image
   * @see UIDefaults.LazyValue
   * @see Icon
   * @see Class#getResourceAsStream(String)
   */
  public static Object makeIcon(final Class<?> baseClass, final String gifFile) {
    return SwingUtilities2.makeIcon(baseClass, baseClass, gifFile);
  }

  /**
   * Returns the <code>LayoutStyle</code> for this look
   * and feel.  This never returns {@code null}.
   * <p>
   * You generally don't use the <code>LayoutStyle</code> from
   * the look and feel, instead use the <code>LayoutStyle</code>
   * method <code>getInstance</code>.
   *
   * @return the <code>LayoutStyle</code> for this look and feel
   * @see LayoutStyle#getInstance
   * @since 1.6
   */
  public LayoutStyle getLayoutStyle() {
    return DefaultLayoutStyle.getInstance();
  }

  /**
   * Invoked when the user attempts an invalid operation,
   * such as pasting into an uneditable <code>JTextField</code>
   * that has focus. The default implementation beeps. Subclasses
   * that wish different behavior should override this and provide
   * the additional feedback.
   *
   * @param component the <code>Component</code> the error occurred in, may be <code>null</code>
   * indicating the error condition is not directly associated with a <code>Component</code>
   * @since 1.4
   */
  public void provideErrorFeedback(Component component) {
    Toolkit toolkit = null;
    if (component != null) {
      toolkit = component.getToolkit();
    } else {
      toolkit = Toolkit.getDefaultToolkit();
    }
    toolkit.beep();
  } // provideErrorFeedback()

  /**
   * Returns the value of the specified system desktop property by
   * invoking <code>Toolkit.getDefaultToolkit().getDesktopProperty()</code>.
   * If the value of the specified property is {@code null},
   * {@code fallbackValue} is returned.
   *
   * @param systemPropertyName the name of the system desktop property being queried
   * @param fallbackValue the object to be returned as the value if the system value is null
   * @return the current value of the desktop property
   * @see java.awt.Toolkit#getDesktopProperty
   * @since 1.4
   */
  public static Object getDesktopPropertyValue(String systemPropertyName, Object fallbackValue) {
    Object value = Toolkit.getDefaultToolkit().getDesktopProperty(systemPropertyName);
    if (value == null) {
      return fallbackValue;
    } else if (value instanceof Color) {
      return new ColorUIResource((Color) value);
    } else if (value instanceof Font) {
      return new FontUIResource((Font) value);
    }
    return value;
  }

  /**
   * Returns an <code>Icon</code> with a disabled appearance.
   * This method is used to generate a disabled <code>Icon</code> when
   * one has not been specified.  For example, if you create a
   * <code>JButton</code> and only specify an <code>Icon</code> via
   * <code>setIcon</code> this method will be called to generate the
   * disabled <code>Icon</code>. If {@code null} is passed as
   * <code>icon</code> this method returns {@code null}.
   * <p>
   * Some look and feels might not render the disabled {@code Icon}, in which
   * case they will ignore this.
   *
   * @param component {@code JComponent} that will display the {@code Icon}, may be {@code null}
   * @param icon {@code Icon} to generate the disabled icon from
   * @return disabled {@code Icon}, or {@code null} if a suitable {@code Icon} can not be generated
   * @since 1.5
   */
  public Icon getDisabledIcon(JComponent component, Icon icon) {
    if (icon instanceof ImageIcon) {
      return new ImageIconUIResource(GrayFilter.
          createDisabledImage(((ImageIcon) icon).getImage()));
    }
    return null;
  }

  /**
   * Returns an <code>Icon</code> for use by disabled
   * components that are also selected. This method is used to generate an
   * <code>Icon</code> for components that are in both the disabled and
   * selected states but do not have a specific <code>Icon</code> for this
   * state.  For example, if you create a <code>JButton</code> and only
   * specify an <code>Icon</code> via <code>setIcon</code> this method
   * will be called to generate the disabled and selected
   * <code>Icon</code>. If {@code null} is passed as <code>icon</code> this
   * methods returns {@code null}.
   * <p>
   * Some look and feels might not render the disabled and selected
   * {@code Icon}, in which case they will ignore this.
   *
   * @param component {@code JComponent} that will display the {@code Icon}, may be {@code null}
   * @param icon {@code Icon} to generate disabled and selected icon from
   * @return disabled and selected icon, or {@code null} if a suitable {@code Icon} can not be
   * generated.
   * @since 1.5
   */
  public Icon getDisabledSelectedIcon(JComponent component, Icon icon) {
    return getDisabledIcon(component, icon);
  }

  /**
   * Return a short string that identifies this look and feel, e.g.
   * "CDE/Motif".  This string should be appropriate for a menu item.
   * Distinct look and feels should have different names, e.g.
   * a subclass of MotifLookAndFeel that changes the way a few components
   * are rendered should be called "CDE/Motif My Way"; something
   * that would be useful to a user trying to select a L&amp;F from a list
   * of names.
   *
   * @return short identifier for the look and feel
   */
  public abstract String getName();


  /**
   * Return a string that identifies this look and feel.  This string
   * will be used by applications/services that want to recognize
   * well known look and feel implementations.  Presently
   * the well known names are "Motif", "Windows", "Mac", "Metal".  Note
   * that a LookAndFeel derived from a well known superclass
   * that doesn't make any fundamental changes to the look or feel
   * shouldn't override this method.
   *
   * @return identifier for the look and feel
   */
  public abstract String getID();


  /**
   * Return a one line description of this look and feel implementation,
   * e.g. "The CDE/Motif Look and Feel".   This string is intended for
   * the user, e.g. in the title of a window or in a ToolTip message.
   *
   * @return short description for the look and feel
   */
  public abstract String getDescription();


  /**
   * Returns {@code true} if the <code>LookAndFeel</code> returned
   * <code>RootPaneUI</code> instances support providing {@code Window}
   * decorations in a <code>JRootPane</code>.
   * <p>
   * The default implementation returns {@code false}, subclasses that
   * support {@code Window} decorations should override this and return
   * {@code true}.
   *
   * @return {@code true} if the {@code RootPaneUI} instances created by this look and feel support
   * client side decorations
   * @see JDialog#setDefaultLookAndFeelDecorated
   * @see JFrame#setDefaultLookAndFeelDecorated
   * @see JRootPane#setWindowDecorationStyle
   * @since 1.4
   */
  public boolean getSupportsWindowDecorations() {
    return false;
  }

  /**
   * If the underlying platform has a "native" look and feel, and
   * this is an implementation of it, return {@code true}.  For
   * example, when the underlying platform is Solaris running CDE
   * a CDE/Motif look and feel implementation would return {@code
   * true}.
   *
   * @return {@code true} if this look and feel represents the underlying platform look and feel
   */
  public abstract boolean isNativeLookAndFeel();


  /**
   * Return {@code true} if the underlying platform supports and or permits
   * this look and feel.  This method returns {@code false} if the look
   * and feel depends on special resources or legal agreements that
   * aren't defined for the current platform.
   *
   * @return {@code true} if this is a supported look and feel
   * @see UIManager#setLookAndFeel
   */
  public abstract boolean isSupportedLookAndFeel();


  /**
   * Initializes the look and feel. While this method is public,
   * it should only be invoked by the {@code UIManager} when a
   * look and feel is installed as the current look and feel. This
   * method is invoked before the {@code UIManager} invokes
   * {@code getDefaults}. This method is intended to perform any
   * initialization for the look and feel. Subclasses
   * should do any one-time setup they need here, rather than
   * in a static initializer, because look and feel class objects
   * may be loaded just to discover that {@code isSupportedLookAndFeel()}
   * returns {@code false}.
   *
   * @see #uninitialize
   * @see UIManager#setLookAndFeel
   */
  public void initialize() {
  }


  /**
   * Uninitializes the look and feel. While this method is public,
   * it should only be invoked by the {@code UIManager} when
   * the look and feel is uninstalled. For example,
   * {@code UIManager.setLookAndFeel} invokes this when the look and
   * feel is changed.
   * <p>
   * Subclasses may choose to free up some resources here.
   *
   * @see #initialize
   * @see UIManager#setLookAndFeel
   */
  public void uninitialize() {
  }

  /**
   * Returns the look and feel defaults. While this method is public,
   * it should only be invoked by the {@code UIManager} when the
   * look and feel is set as the current look and feel and after
   * {@code initialize} has been invoked.
   *
   * @return the look and feel defaults
   * @see #initialize
   * @see #uninitialize
   * @see UIManager#setLookAndFeel
   */
  public UIDefaults getDefaults() {
    return null;
  }

  /**
   * Returns a string that displays and identifies this
   * object's properties.
   *
   * @return a String representation of this object
   */
  public String toString() {
    return "[" + getDescription() + " - " + getClass().getName() + "]";
  }
}
